Contamination Control - doe-std-1128-98

DOE-STD-1128-98

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CONTAMINATION CONTROL

The primary control for contamination in a plutonium plant is the facility design.

Contamination is confined primarily by enclosing the process areas and using controlled

ventilation systems. Appendix C of this guide addresses the different levels of confinement

in a plutonium facility. The design objective for the confinement system is to essentially

prevent or minimize exposure of plant personnel and the public to airborne contamination.

To ensure that this objective is met, additional attention should be given to air

contamination control, surface contamination control, and personnel contamination control.

Radiological controls for the workplace should ensure that radionuclides are contained and

handled properly and that intakes, if they occur at all, are negligible to the extent achievable

with state-of-the-art technology. However, much of the current effort involves

decommissioning of no-longer-needed production facilities. The lack of engineered

controls or the systematic removal of existing controls during the decommissioning process

introduces a completely different set of circumstances that requires special attention for

adequate contamination control and worker and public protection.

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AIR CONTAMINATION CONTROL

To achieve the design objective of preventing (or at least minimizing) internal exposure of

plant personnel, airborne contamination must be confined to process enclosures which have

adequate air cleaning systems. Because both equipment and personnel errors can

compromise designed protection and because older facilities may already have unconfined

plutonium, air monitoring and other contamination control measures are needed.

Experience has shown that the most common route for inadvertent plutonium deposition in

man is by inhalation even though intakes may also occur by accidental ingestion or by

wound contamination. In facilities being decommissioned, the use of temporary

containment structures, interim ventilation systems, and administrative controls such as

protective clothing and respirators may be required to replace engineered systems.

10 CFR 835.1002 requires that for the control of airborne radioactive material, the design

objective shall be, under normal conditions, to avoid releases to the workplace atmosphere

and in any situation, to control the inhalation of such material by workers to levels that are

ALARA; confinement and ventilation shall normally be used. See Appendix C for Facility

Design guidance.

Note: The use of ventilation systems may require the approval of Facility Criticality Safety

personnel because these systems may concentrate fissionable material.

4.1.1 Internal Versus External Dose Philosophy

The overall goal of radiological protection is to minimize the total dose to the

individual. However, because of the difficulties and cost of an adequate internal

dosimetry program for plutonium exposure, it is best to avoid all internal exposures

during routine operations and anticipated abnormal events by facility design features

and personnel protective equipment. As stated above, this is an extremely challenging

goal for those facilities in environmental remediation. The conditions encountered in

decommissioning and environmental restoration will typically place a heavy reliance

on administrative controls.

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